Tide-generating force
Topic: Movements of Ocean Water: Waves, Tides and Currents · NCERT: Class 11, Ch 13 "Movements of Ocean Water"
Meaning
The tide-generating force is the force that creates tides. It is the difference between the Moon's gravitational pull and centrifugal force (the outward force that balances gravity). On the side facing the Moon, the pull is stronger, so water bulges towards the Moon. On the far side, the pull is weaker and centrifugal force wins, so a second bulge forms away from the Moon. The horizontal (sideways) part of this force does more to pile up water than the vertical part. The Sun adds a smaller force. The Moon's pull is more than twice the Sun's.
Example
Because of this force, the Gulf of Khambhat in Gujarat sees the sea rise and fall twice a day. Its funnel shape greatly increases the tidal range.
Don't confuse with
- Storm surge: a rise in sea level pushed by wind and low air pressure. It is irregular, so it is not a tide.